"The court denies all the accused persons bail," ruled magistrate Marehwanazvo Gofa after two days of hearings in the capital, Harare.

He said the staffers were facing serious charges including breaching state secrets laws, and so did not qualify for bail.

Beatrice Mtetwa, a prominent human rights lawyer who has represented the opposition and rights activists, was also denied bail after her arrest for allegedly shouting at the police during a raid of the prime minister's communications office on Sunday.

"The commotion and shouting can hinder the police in carrying out their investigations accordingly. Bail application is denied," Gofa said.

A court had earlier ordered Mtetwa's release from police custody, but the order was ignored by police.

The five detainees will appear in court again on April 3 and 4, the judge ruled on Wednesday.

Defence lawyers said they planned to appeal the bail denial at the country's high court.

The arrests marred a largely peaceful referendum on Saturday on a new constitution, which was approved by nearly 95% of voters.

The constitution is meant to pave the way for new elections to replace Tsvangirai's uncomfortable power-sharing government with his arch-rival, veteran President Robert Mugabe.

The charter curtails the president's powers and sets a limit of two five-year terms.
– Sapa-AFP